Toys of the type referred to above have been designed either as a vehicle engaging frictionally the inside of a spherical shell by two wheels at a maximum distance--i.e. so that the points of contact will be located oppositely at a diameter of the shell--or they have been designed as a hollow shell containing a body which is movable relative a diametrically arranged shaft in the shell.
The U.S. Pat. No. 4,541,814 discloses a toy of the first mentioned type. It has a steering wheel mounted diametrically opposite a driving wheel making it difficult to perform distinct movements in any direction.
The U.S. Pat. No. 4,726,800 shows an example of the other of the said two types of known toys.
According to the '800 patent a shaft is rigidly mounted in a hollow shell and said shaft is carrying a chassi the gravity center of which is located at a distance from the shaft. A motor is used for causing relative movements between the chassi and the shaft.
This type of toy has also the drawback that distinct shifts of movements of the toy are difficult to obtain.